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The mechanisms operative in the initiation, expression, and downregulation of skin-derived immune responses. Induction of T cell immunity via the skin:
Antigens administered to or occurring in the skin (microbial products, haptens, etc.) will be picked up, engulfed, processed and presented by dendritic
antigen-presenting cells in the epidermis (LC = Langerhans cells) and/or the dermis (DDC = dermal dendritic cells). When danger signals, particularly
those reaching beyond the dermal–epidermal junction, are present at the time of antigenic exposure, these DC will undergo a process of maturation as
evidenced by an enhanced expression of MHC antigens, costimulatory molecules (CD80, CD86, CD40, CD83, etc.), and immunostimulatory cytokines (IL1β, IL-6, IL-12, IL-23) as well as their enhanced emigration from the skin to the paracortical areas of the draining lymph nodes. At this site, the skin-derived
Source: Chapter 10. Innate and Adaptive Immunity in the Skin, Fitzpatrick's Dermatology in General Medicine, 8e
DCs provide activation stimuli to the naive resting T cells surrounding them. This occurs in an antigen-specific fashion and thus results in the expansion of
Citation:
Goldsmith
SI, Gilchrest
Pallerskin-homing
AS, Leffell DJ,
Wolff K.(e.g.,
Fitzpatrick's
in General
Medicine,
8e; 2012 Available
the respective
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thusKatz
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express
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well as receptors
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at:
http://mhmedical.com/
Accessed:
August
03,
2017
promote their attachment to dermal microvascular endothelial cells of inflamed skin and, ultimately, their entry into this tissue. Elicitation of T-cell-mediated
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© pathogen
2017 McGraw-Hill
Education.
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rights
reserved
tissue inflammation
and
clearance:
on receipt
a renewed
antigenic stimulus by activated skin DCs or other APCs, the skin-homed T cells
expand locally and display the effector functions needed for the elimination of the pathogen. Downregulation and prevention of cutaneous T cell immunity: